Question

A battery has an internal resistance $4\Omega$ is connected to the network of resistance as shown. What must be the value of $R$ (in $\Omega$) so that maximum power is delivered to the network ?

• A. $4\Omega$
• B. $3\Omega$
• C. $2\Omega$
• D. $1\Omega$

Answer 1

The correct option is C $2\Omega$




According to maximum power transfer theorem,

$R_{ext}=R_{int}.......\left(1\right)$

The given circuit is a balanced Wheatstone bridge, its equivalent resistance is,

$R_{eq}=\frac{3R\times 6R}{3R+6R}=2R$

From (1) we get,

$2R=4$

$R=\frac{4}{2}=2\Omega$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(C\right)$ is the correct answer.